

Signing (intermediate) certs have been compromised before. That means a bad actor can issue fake certs that are validated up to your root ca certs
While you can invalidate that signing cert, without useful and ubiquitous revocation lists, there’s nothing you can do to propagate that.
A compromised signing certs, effectively means invalidating the ca cert, to limit the damage

As everyone else says, look at home bridge. I use HA for my automation but use the bridge to expose many devices to HomeKit.
I verified I can set up HomeKit and use family share for my family to see the dashboards I set up there